To obtain a flame-retarded composition improved in flame retardancy in spite of having no halogen or phosphorus compound and in mechanical properties by dispersing in a resin a layered double hydroxide showing a specified maximum base interplanar spacing as measured by the powder X-ray diffraction.

A layered double oxide showing the maximum basic interplanar spacing (d003) of 9 as measured by the powder X-ray diffraction is added to a resin, and the mixture is uniformly mixed with a kneader such as a mixing roll, a Banbury mixer, a pressure kneader, a twin-screw kneader, or a KCK kneader to discretely disperse the layered double hydroxide. The layered double hydroxide means a compound in which many layers are piled through ions or an organic compound such as glycerol, a glycol, a fatty acid, a fatty acid salt, an oligomer, an epoxy resin, a polyolefin resin, or maleic anhydride modified polyolefin resin among the layers of a metal hydroxide. The resin may be either of a thermoplastic resin or a thermosetting resin.